Telephone system



July 15, 1924. 4 1,501,648

R. D. CONWAY TELEPHONE SYSTEM 041/04 fan EoyD. (oz/way Filed Aug. '7.

Patented July 15, 1924.

UNITED STATES PATENT OFFICE.

ROY DOUGLAS CONVJAY, OF CHATHAM, NEXV JERSEY, ASSIGNOR TO WESTERN ELEG- TRIC COMPANY, INCORPORATED, 015 NEW YORK, N. Y., A. CORPORATION OF NEW YORK.

TELEPHONE SYSTEM.

Application filed August 7, 1920. ,Serial No. 401,907.

To uZZ whom it may concern:

Be it known that I, Roy D. CONWAY, a citizen of the United States, residing at Chatham, in the county of Morris and State of New Jersey, have invented certain new and useful Improvements in Telephone Systems, of which the following is a full,

clear. concise, and exact description.

This invention relates to improvements in telephone systems, and has particular refer-- ence to a line switching device of the cross bar type.

Heretofore. it has been customary, if all of the trunks terminating in a switch of this type are busy, to continuously operate the switch over the test terminals of the trunks until one of them becomes idle, whereupon the switch comes to rest and the idle trunk is preselected.

An object of the present invention is to prevent the further testing in an attempt to preselect a trunk when all but one of the trunks are busy and the remaining one preselected Another object of the invention is to operate a register or signal when all trunks are taken for use in a switch of this charac ter.

The drawing is a fragmentary perspec- 0 tive view of the switch and a diagram of circuits for operating the same,

In the drawing, 1 indicates a portion of the frame of the switch in which a plurality of line bars 2 are pivotally mounted by links 3 and at. Each line bar is provided with sets of terminals 5 6, 7 and 8, the terminals of each set being insulated from each other and said sets being equal in number to the number of trunks to which the switch has access. Also pivotally mounted in the frame 1. are a plurality of trunk bars 9, disposed at right angles to the line bars and each provided with sets of contact members 10, 11, 12 and the members of each set being insulated from each other. The number of sets of contact members on each trunk bar is equal to the number of line bars employed, In the operation of the switch, ne of the trunk bars will normally be slightly rotated or in a preselected position so that when a line bar is operated, upon the initiation of a call, a set of terminals of said line bar will engage associated sets of contact members on the preselected trunl: bar. The movement of the line bar is such as to position the remaining sets of terminals thereon where they cannot be engaged by contact members of any of the other trunk bars while the line bar is operated. Upon the engagement of the terminals and contact members of the line and trunk bars, the displaced or preselected trunk bar is restored to normal to carry its unengaged contact members out of position to be engaged by the terminals of another line bar which may be subsequently operated. The preselection of a trunk bar is accomplished by the energization of a magnet 14 which, by means of a pawl 15, controls a rotatable set rod 16 having a plurality of spirally arranged pins 17 so disposed that only one of them at a time will be placed opposite the respective latch 18 carried by the trunk bar. The circuit. for operating magnet 14 extends through test contacts 19 carried by a ring 20 surrounding the rod 16. Cooperating with contacts 19 is a flexible wiper 21 fixed to set rod 16, and engaged by brush 22 whereby, as the rod rotates, the wiper 21 will engage the various contacts and test for an idle trunk. llpon finding such a trunk, thecircuit for magnet 14 is opened and the pin 17 associated with said trunk will be positioned opposite the latch 18 thereof. The set rod magnet 23, which is slower to operate than the magnet 14, is then energized to move the set rod to the left. as viewed in the drawing, thereby moving the latch 18 in a similar direction to displace and preselect the idle trunk bar. In this movement, the latch 18 engages an adjacent lug 24 carried by a latch bar 25 pivotally mounted in frame 1 to force the said bar downwardly against the tension of a spring 82. This downward movement releases the. latch 18 of any other previously selected trunk bar, the seizure of which resulted in the preselection of another bar. The seized trunk bar then returns to its nor mal position with the exception of the set of Contact members thereof, which are in engagement with the terminals of a line bar. These contact members then assume the position shown on the trunk bar 9 at the right of the drawing and the remaining sets of contact members are then in a position where they cannot be engaged by the terminals of other line bars. After the latch 18 of the preselected trunk bar has passed over the associated lug 24, the latch bar 25 returns to-normal and the lug engages the latch to prevent the return of the trunk bar to normal until the said bar is seized for use. During the preselection of any trunk and before the same is seized the latch 18 thereof engages a projection 30 carried by a rod 31 to move said rod to a position where the same will open contacts 32 and 38 to prevent the energization of magnet 28 over a circuit through said contacts. Contact 33 is of sufficient resiliency to force rod 31 back towards its normal position when the latch 18 of the preselected trunk bar restores upon the seizure of the trunk associated therewith.

The invention contemplates the provision of means for operating a register or similar device when all the trunks terminating in the switch are busy. To this end use is preferably made of a latch 26, similar to the other latches 18. and pivoted to the frame 1 in any suitable manner. Another pin 17 is associated with the latch 26 and a test contact 27. similar to contacts 19. is provided on the ring 20. If any one of the trunks terminating in the switch is idle. a ground potential will be found upon the contact 27. in a manner which will later appear. and magnet 14 will therefore step the wiper 21 over said contact when said idle trunk is be ing preselected. With a trunk preselected and all the remaining trunks busy this ground potential is removed and wiper 21 comes to rest upon contact 21 and pin 1?. associated with latch 26. will be in the posi tion shown in the drawing. Then, upon. the seizure of the preselected trunk, and provided that no other trunk has become idle in the meanwhile. set rod 16 moved longitudinally by magnet 22 and contacts 28 are closed to energize the meter magnet 29 to advance the counting train one step. Au indicator in the form of a signal lamp. in stead of the meter. may be operated earl.- time all but one of the trunks are busy the remaining one is. preselected. This si nal is shown a lamp 80. arranged to be substituted for the meter by a manual switch 81. The movement of the set rod moves latch 26 to the left and over and behind the lug 21 associated therewith. so as to force the latch bar 25 downwardly and release t.

latch 18 of the preselected trunk bar that has been seized. Inasmuch as latch 26 hr no lug 30 associated therewith, the rod is permitted to return to normal position. and close the contacts 32 and 38 when the latch 18 of the seized trunk bar restores. The latch 26 remains in its operated position until a trunk becomes idle. whereupon magnet 14 is operated to step the test wiper 21 over the contacts 19 until the contact individual to the idle trunk is engaged. Magnet is then operated to move the set rod 16 to the left and preselet the idle trunk. The latch 18 of the idle trunk bar, in passing over its lug 24:, releases the latch 26 which then returns to normal. Latch 18 of the preselected trunk bar also engages its associated projection to move rod 31 to the left to open contacts 32 and 33 and thus release magnet 23.

It. while the pin 17 is opposite latch 26 and at the time that the preselected trunk is seized, another trunk should becomeidle. the magnet 14. being quicker to operate than magnet 2?, will he energized to rotate set rod 16 through a circuit extending to ground on contact 27 and will. continue to rotate said set rod as long the wiper 21 engages grounded contarts 19. Nhen the ungrounded contact 15 of the idle trunk is reached, magnet 14 will cease to operate and the pin 17. associated with latch 18 of the idle trunk bar, will be positioned opposite said latch. The trunk bar is then displaced and moved to its preselected position by the energization of the magnet as before described.

It is believed that the invention will now be tully understood from the following detailed description ot the operation in extending a call from substation 3st. lVith the trunk bar 9. shown at the right of the drawing. and the remaining trunk bars. (not shown) busy. and the trunk bar at the left of the drawing preselected, relays and 35 and all other relays individual to the remaining busy trunk bars are energized and locked up to the test conductors of their res1 er-tive trunks. while relay 8?. individual to the preselected trunlt bar. shown at the left of the drawing is in its normal position and :--emains So until the Jreselected trunk is seized. These relays 3 ,6, 37, etc, may be located at a succeeding ,lector switch if desired. Under these conditions. upon the removal ot the receiver from its switch hook at substation a circuit is established for line relay 88. traceable from grounded battery through the winding of said relay. the normally closed contacts 39 and 4-0. the lower side of the subscribefis line. the substation apparatus. the upper side of the sub s'ribers line and the normally closed contacts 1-1 and 1-2 to grmind. Relay energizes in thi circuit and in attracting its armature closes the normally open contacts and a l: and also moves the lever into the path of upward movement of an extension. 46 carried on an operating bar 4-7. The closure of the contacts 4:3 and. L4- establishes circuit extending from ground through said contacts. windings of magnet a8 and the normally closed contacts 49 and 50 to grounded battery. Magnet 48 is energized and in attracting its armature. moves the operating bar 47 upwardly to ause extension 46 to engage lever and thus rock the links 3 and i of the line bar 2 individualv to Substation 34 about their pivots. The line bar 2 is thus moved upwardly and to the left to engage terminals 5, 6, 7 and 8 with adjacent contact members 10, 11, 12 and 13 of the preselected trunk bar. The engagement of these terminals and contact members c on nectthe seized trunk to the subscribers line, whereupon the line relay of the succeeding selector switch will be operated to ground the test conductor 51 of said trunk in any manner well known in the art. A circuit is thus established for the holding relay 52 extending from grounded battery through the winding of said relay, terminal 7, contatt member 12 and test conductor 51 to ground at the succeeding switch. Relay 52 energizes and in attracting its upper armature, which preferably forms a portion of the links 3 of the line bar, maintains said line bar in its operated position throughout the duration of the call. By attracting its lower armature, relay 52 opens the normally closed contacts 39, and 41, 42 and closes the normally open contacts 53 and 54 to extend the subscribers line through the latter contacts to the seized trunk and succeeding switch. The opening of the normally closed contacts before mentioned, breaks the energizing circuit for line relay 38 which thereupon releases to open the energizing circuit for magnet 48, whereupon operating bar 47 restores to normal. The release of the armature of-relay 38 also permits the V lever to return to normal under the influence of a spring 55. Upon the completion of the circuit through contacts 53, 54 to the succeeding switch, the conductor 56 extending thereto is also grounded in any well known manner to establish an energizing circuit for the relay 37 individual to the seized trunk. This relay then locks through its upper armature to ground on the conductor 51 of said trunk. The subscriber at substation34 may now operate his impulse sending device to transmit series of impulses whereby succeeding switches may be operated to connect the subscribers line to a called substation.

Now that all the trunks terminating at the line switch are busy, magnet 14 will notoperate through the lower contacts of any of the relays 36, 37, etc., and a circuit will be established from ground through the test conductor 51. closed contacts 57 and 58, the windings of magnet 23 and the closed contact-s and 60 to grounded battery. Magnet 23 energizes in this circuit and moves set rod 16 to the left to cause pin 17 to movelat?-h 26 in a similar direction. As the latch 26 moves over its associated lug 24, latch bar is forced downwardly to disengage lug 24 associated with the latch 18 of theseized trunk bar. whereby set latch 18 and said trunk bar arerestored to normal. The contact members 10, 11, 12 and 13 of the trunk bar engaged with terminals 5, 6, 7 and 3 of the line bar remain engaged therewith and are flexed as shown by the lower set of contact members on the trunk bar at the right of the drawing. The release of the latch 18 permits the contacts 61 and 62 to return to normal and in so doing contact 62 engages the contact 5?, whereby the busy ground potential on the conductor 51 is extended through these contacts to the test contact 19 individual to the seized trunk bar. The movement of contact 62 to normal, also opens contacts 57 and 58 to break the energizing circuit for magnet The move ment of contact 61 to normal extends ground through contaats 63 and 61 to the lower contact of relay 3'7, but this relay being new energized and locked up, this ground is not extended beyond this point. The movement of the set rod 16 to the left, in every instance upon the energization of the magnet 23 as previously described, in addition to open ating latches 18 and 26, also opens contacts 49 and 56 to prevent the energization of magnet 48. As the latch 26 is operated and passed beyond its associated lug 24, the latch bar 25 moves upwardly so as to engage said lug 24 with the latch 26 in such a manner as to prevent the return thereof to normal. The movement of the latch 26 to the left, closes contacts 28 to establish a circuit for meter magnet 29, or it the switch 81 is shifted, to close a circuit for lamp S0. The relays 35., 36, 37, etc., being now all energized, the ground through the contacts 61 and 63 individual to the several trunk bars will be disconnected from the common conductor 64 extending to the contact 27, so that a circuit will not be established through said conductor, wiper 21, brush 22, contacts 6"- and 66, winding of magnet 14 to grounded battery. Magnet 14 will, therefore, remain idle and wiper 21 will continue to engage contact 27 until one of the trunks terminating in the switch becomes idle.

At the time latch 26 is operated and the latch 18 of the preselected and seized trunk restores to normal, the bar 31 is also restored since the latch 26 does not engage the projection 30 on said rod. This permits of the contacts 32 and 33 closing to prepare a circuit for the magnet 23, but this circuit is not completed inasmuch as relays 35, 36, and 37 and other similar relays are energized. As soon as a trunk becomes idle, ground is removed from the conductor 51 of said trunk which extends through contacts 57 and 62 individual to the trunk bar to the test contact 19. The removal of ground from conductor 51 also causes the release of holding magnet 52 which permits of the return of the line bar 2 individual to the calling line to return to normal position. Assuming that the trunk terminating in the trunk bar 9 at the right ofthe figure, is the first one to heroine idle, the locking circuit for relay 36 individual to said trunk will be opened by the removal of ground from the test conductor 51 of said trunk and said relay will deenergize. Magnet 14, being quicker to operate than magnet 23, will then be energized over a circuit extending from grounded battery through the winding of magnet 14,0011- tacts 66 and 65, brush 22, wiper 21, test contact 27, common conductor 64, the lower contact of relay 36, and contacts 61 and 63 of the trunk bar to ground. Magnet 14 operates to cause pawl 15 to rotate set rod 16 onto the next succeeding contact 19 and, un der the assumption that the trunk to which said contact is individual is busy, the wiper 21 will find ground on said contact extending through the contacts 62 and 57 of the busy trunk bar to the test conductor 51 of the trunk. Magnet 1 1, will, therefore, continue to operate through its self-interrupting circuit until test wiper 21 engages contact 19 free from. ground It will be obvious that the energization of the magnet 14 also interrupts the energizing circuit for magnet 23 and the latter magnet will, therefore, not operate until magnet 14- becomes permanently deenergized. At this time the circuit tor magnet 23 through contacts 82 and 33 will be closed to ground over the common conductor 64 and lower contact of relay 36, and set rod 16 will therefore, be moved to displace the idle trunk bar. When being moved to its preselected position, latch 18 of said trunk bar engages the associated pro,- jection 30 on the rod 31 to move the same to the left, thereby opening the contacts 32 and 33 to break the circuit for magnet 23, which thereupon releases to permit set rod 16 to restore. The trunk bar 9 at the right of the drawing is now in a preselected position and upon seizure thereof, the cycle of operations continues in the same manner as hereinbefore described WVhat is claimed is:

1. In a switching mechanism, a plurality of trunk bars, means for preselecting a trunk bar, means for seizing the preselected trunl: to render the same busy, a register. and means operable when all the trunk bars become busy for controlling said register.

In a switching mechanism, a plurality of trunk bars, means for testing for an idle one of said trunk bars, means thereupon op-- erated to preselect the idle trunk bar, means for seizing the preselected bar, and means operable when all but one of the bars are busy and the remaining one preselected for rendering said testing means ineffective.

3. In a switch mechanism, a plurality of trunk bars, means for testing for an idle one of said trunk bars, means thereupon operated to preselect the idle trunk bar, means for seizing the preselected bar, means operable when all but one of the bars are busy neonateand the remaining one preselected for rendering said testing means inetl ective,'and register controlling means actuated upon the seizure of the remaining preselected bar.

4. In a switching mechanism, a plurality of trunk bars, testing contacts for said trunk bars, another contact associated with said testing contacts, a test wiper engageable with said contacts, means operable to preselect one of said trunk bars, and means for stopping said test wiper on said other contact when all but one of the trunk bars are busy and the remaining bar preselected 5. In a switching mechanism, a plurality of trunk bars, testing contacts for said trunk bars, another contact associated with said testing contacts, a test wiper engageable with said contacts, means operable to preselect one of said trunk bars, means for stopping said test wiper on said other contact when all but one of the trunk bars are busy and the remaining bar preselected, and reg ister controlling means actuated upon the seizure of the preselected trunk bar.

6. In a switching mechanism, a plurality of trunk bars, testing contacts for said trunk bars, another contact associated with said testing contacts, a test wiper engage able with said contacts, means operable to preselect one of said trunk bars, means for stopping said test wiper on said other con tact when all but one of the trunk bars are busy, and the remaining bar preselected, register controlling means actuated upon the seizure of the preselected trunk bar, and means for moving said wiper from said other contact engagement with said test contacts when one of said trunk bars becomes idle.

7. In a switching-mechanism, a plurality of trunk bars, test contacts for said trunk bars, another contact associated with said test contacts, a test wiper engageable with said contacts, means operable to preselect one of said trunk bars, means for seizing the preselected trunk bar to render same busy,-

a common mechanism operable when a trunk bar is preselected for releasing a seized trunk bar, and means for stopping said test wiper on said other contact when all but one of the trunk bars are busy and the re- 1 maining bar preselected.

8. In a switching mechanism, plurality of trunk bars, test contacts for said trunk bars, another contact associated with said test contacts, a test wiper engageable with said contacts, means operable to preselect one of said trunk bars, means for seizing the preselected trunk bar to render same busy, a common mechanism operable when a trunk bar is preselected for releasing a. seized trunk bar, means for stopping said test wiper on said other contact when all but one of the trunk bars are busy and the remaining bar preselected, and electromagnetic means for controlling a register actuated upon seizure of a preselected trunk bar when all others bars are busy.

9. In a switching mechanism, a plurality of trunk bars, test contacts for said trunk bars, another contact associated with said test contacts, a test wiper engageable with said contacts, means operable to preselect one of said trunk bars, means for seizing the preselected trunk bar to render same busy, a common mechanism operable when a trunk bar is preselected for releasing a seized trunk bar, means for stopping said test wiper on said other contact when all but one of the trunk bars are busy and the remaining bar preselected, electromagnetic means for controlling a register actuated upon seizure of a preselected trunk bar when all other bars are busy, and means for moving said wiper'from said other contact into engagement with said test contacts when one of said trunk bars becomes idle.

10. In a switchin mechanism a plurality of trunk bars, means for selecting and operating sad bars when idle, means for rendering an operated bar non-selectable, an indioator, and means for operating said indicator when all said bars become busy,

11. In a switching mechanism a plurality of trunk bars, means for testing said bars in succession and operating an idle bar, means for rendering an operated bar nonselectable, an indicator, and means for operating said indicator when all said bars become busy.

In Witness whereof, I hereunto subscribe my name this 4th day of August, A. 1)., 1920.

' ROY DOUGLAS CONWAY. 

